[Influence of donor profile on pre and post-pasteurization bacteriology of donated human milk]. / Influencia del perfil de las donantes en la bacteriología pre- y pospasteurización de la leche humana donada.

Introduction: Introduction: breastfeeding is the gold standard for infant's nutrition. Human milk bank is an essential tool to guarantee availability and safety in those situations when breastfeeding is not an option. The manipulation during the extraction of the human milk by the donors is a critical point to ensure an adequate microbiological safety. Therefore, knowing the bacterial flora that prevails in donated milk is essential to draw conclusions that can lead to taking measures in the management of the bank. Objectives: to analyze the prevalence of microorganisms in milk samples donated to the milk bank and how the bacterial flora behaves according to the profile of the donors and the donor milk circuits. Methods: the present work is a retrospective descriptive observational study that analyzes characteristics and the positive microbiological results within our milk bank samples from June 1, 2016 to December 31, 2020. All milk bank donors voluntarily signed an informed consent that authorizes the use of data to investigation. Results: during the study period, a total of 1,587 liters of raw milk were donated by 266 women, highlighting that, despite the SARS-CoV-2 virus pandemic, 2020 has been the year in which more volume of milk has been dispensed. The results show that 221 batches had at least one positive microbiological isolation (149 of them were before and 46 after pasteurization). Pre and post-pasteurization rate varies over the years with a decrease in the pre-pasteurization discard rate (3,9%) and increase in the post-pasteurization rate (5,3%). The most frequently isolated germs found in pre-pasteurization cultures were gram positive cocci and Enterobacter and a decrease in the positivity to S. aureus after establishing an eradication protocol. In post-pasteurization cultures, the most commonly found germs are Bacillus. Regarding the donor's profile, it was found a non statistically significant way that those women with the highest donation volume and/or admission of their offspring in Neonatology were associated with higher frequency of positive cultures. Conclusions: bacteriological analysis of milk samples is an essential part of quality control for a milk bank. Our results reflect a good extraction system and transportation, as well as good training from the bank's professionals. Nevertheless, improvement of processes is necessary to reduce the rate of contamination and the amount of discarded milk.

Introducción: Introducción: la leche humana es el patrón oro en la nutrición de los neonatos. Por ello, los bancos de leche se convierten en elementos esenciales para garantizar su disponibilidad y seguridad cuando la leche materna no está disponible. La manipulación que se realiza de la leche es un punto crítico para asegurar la seguridad microbiológica de las muestras. Por ello, analizar la flora de la leche donada es fundamental para tomar medidas de mejora de los bancos de leche. Objetivos: analizar los resultados microbiológicos positivos en un banco de leche humana entre las muestras de leche cruda donadas y tras su pasteurización y evaluar si existe relación entre los aislamientos, el perfil de la donante y los circuitos de leche donada. Métodos: estudio observacional descriptivo que analiza las características de la leche donada y los resultados microbiológicos positivos de muestras de leche donadas en nuestro banco desde junio de 2016 hasta diciembre de 2020. Todas las donantes firmaron un consentimiento informado. Resultados: durante el período de estudio fueron donados 1587 litros de leche cruda por 266 mujeres destacando que, a pesar de la pandemia, 2020 ha sido el año en el que más volumen se ha dispensado (280 L). Se obtuvieron 221 lotes de leche con al menos un aislamiento microbiológico positivo (14,2 % total), de ellos 149 previos y 46 posteriores a la pasteurización. La tasa de descarte pre y pospasteurización es variable a lo largo de los años con descenso en 2020 prepasteurización (3,9%) e incremento pospasteurización (5,3%). Los gérmenes más frecuentemente aislados fueron cocos grampositivos, seguidos por Enterobacterias prepasteurización detectándose un descenso en la positividad a S. aureus tras establecerse un protocolo de erradicación. En las muestras pospasteurización predomina el género Bacillus. Se ha encontrado una relación aunque no estadísticamente significativa (p > 0,05) entre mujeres con mayor volumen de donación y/o ingreso de su hijo/a en Neonatología y una mayor frecuencia cultivos positivos. Conclusiones: el análisis bacteriológico de las muestras es parte fundamental del control de calidad. Nuestros resultados traducen una buena sistemática de extracción y transporte, así como un buen entrenamiento de los profesionales del banco. No obstante, es necesario mejorar los procesos para reducir la tasa de contaminación y la cantidad de leche desechada.

Donor Milk Banking - Safety, Efficacy, New Methodologies.

Donor milk (DM) is of increasing interest as primary nutritional source for preterm infants. Safe access requires special infrastructure, trained staff, sophisticated algorithms, and standard operating procedures as well as quality control measures. DM has limitations like low protein content and unpredictable composition of the other macronutrients, despite fortification frequently not meeting recommendations - both of them compromising growth. The first paragraph is devoted to COVID-19 and how it impacts processes of DM banking. The following paragraphs review aspects of "pasteurization," "safety audits/donor screening," and "DM nutrient variability." In summary, (i) Holder pasteurization still is the most suitable procedure for milk banks, but high-pressure pasteurization or ultraviolet C irradiation conserve the unique properties of DM better and deserve more research to make it suitable for clinical routine. (ii) In regard to safety/screening, guidelines are valuable for safe DM bank operation, but they differ between legislations. There is a surprisingly high rate of non-disclosed donor smoking (0.3%, p > 0.05) and of adulteration of delivered DM (up to 2%, p < 0.05) not detected by standard donor screening procedures. Frequencies differ between remunerated and non-remunerated programs. (iii) Neonatal caregivers should be aware of unpredictable composition of DM. They should be trained on how these can be overcome to avoid negative impact on growth and long-term outcomes like (a) measuring and disclosing nutrient contents of delivered DM batches to customers, (b) implementing certain types of donor pooling to reduce the risk of macronutrient depleted DM, (c) additional supplementation using 0.3-0.5 g protein/100 mL seems to be reasonable, (d) adjusted fortification may help to improve growth, but is not efficient in all preterm infants, (e) target fortification seems to improve growth (and probably also neurodevelopmental index) compared to standard fortification, (f) more research and clinical studies are needed.

Pasteurization, storage conditions and viral concentration methods influence RT-qPCR detection of SARS-CoV-2 RNA in wastewater.

The COVID-19 pandemic presents many public health challenges including the tracking of infected individuals from local to regional scales. Wastewater surveillance of viral RNA has emerged as a complementary approach to track and monitor the presence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in a variety of communities of different land use and population size. In the present study, we investigate how five different parameters (pasteurization, storage temperature, storage time, polyethylene glycol (PEG) concentration, and pellet mass) affect the detection of the SARS-CoV-2 N gene and fecal abundance indicator pepper mild mottle virus (PMMoV) gene. Pre-treatment of 24-h composite wastewater samples (n = 14) by pasteurization at 60 °C resulted in a significant reduction of total RNA concentration and copies of the SARS-CoV-2 N gene copies/L (paired Student's t-test, P < 0.05). Comparing the wastewater samples collected from 6 wastewater treatment plants (WWTPs) for a storage period of 7 and 14 days at 4 °C, -20 °C and -80 °C, demonstrated a decrease in SARS-CoV-2 N gene copies/L when samples were stored for 14 days at -20 °C. Polyethylene glycol-NaCl for purification and concentration of viral particles from the wastewater samples demonstrated that a short PEG incubation of 2 h during centrifugation at 4 °C was sufficient for the consistent detection of the SARS-CoV-2 N gene from a 30 mL sample volume. Combined, this paper presents method recommendations for developing a reliable, accurate, sensitive, and reproducible estimation of the SARS-CoV-2 virus in diverse domestic wastewater samples.

Human Milk SARS-CoV-2 Antibodies up to 6 Months After Vaccination.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies have been detected in human milk up to 6 weeks post-coronavirus disease 2019 (COVID-19) vaccination. We evaluated SARS-CoV-2-specific antibodies, neutralization activity, effect of pasteurization, and persistence through 6 months after vaccination. METHODS: This prospective longitudinal study enrolled 30 pregnant or lactating women. SARS-CoV-2 antibodies and neutralization capacity were analyzed using an enzyme-linked immunosorbent assay compared at prevaccination and 1, 3, and 6 months postvaccination, and through Holder pasteurization. RESULTS: Human milk SARS-CoV-2-specific IgG levels peaked at 1 month postvaccination and persisted above prevaccination levels for at least 6 months (P = .005). SARS-CoV-2-specific IgA was detected at 1 and 3 months (both P < .001) but waned by 6 months compared with baseline (P = .07). Milk SARS-CoV-2-specific IgG and IgA correlated with serum IgG at the same time point (R2 = 0.37, P < .001 and R2 = 0.19, P < .001). Neutralization activity was seen in 83.3%, 70.4%, and 25.0% of milk samples at 1, 3, and 6 months postvaccination. Neutralization most strongly correlated with SARS-CoV-2-specific IgG (R2 = 0.57, P < .001). Pre- and postpasteurization samples showed similar IgG (0.84 vs 1.07, P = .36) and neutralizing activity (57.7% vs 58.7% inhibition, P = .27), but lower IgM and IgA levels postpasteurization (0.09 vs 0.06, P = .004 and 0.21 vs 0.18, P = .043). CONCLUSIONS: The data suggest that human milk SARS-CoV-2-specific antibodies may be available to milk-fed infants for up to 6 months. In addition, donor milk from vaccinated mothers retain IgG and neutralizing activity.

Human Milk from Previously COVID-19-Infected Mothers: The Effect of Pasteurization on Specific Antibodies and Neutralization Capacity.

BACKGROUND: Since the outbreak of coronavirus disease 2019 (COVID-19), many put their hopes in the rapid availability of effective immunizations. Human milk, containing antibodies against syndrome coronavirus 2 (SARS-CoV-2), may serve as means of protection through passive immunization. We aimed to determine the presence and pseudovirus neutralization capacity of SARS-CoV-2 specific IgA in human milk of mothers who recovered from COVID-19, and the effect of pasteurization on these antibodies. METHODS: This prospective case control study included lactating mothers, recovered from (suspected) COVID-19 and healthy controls. Human milk and serum samples were collected. To assess the presence of SARS-CoV-2 antibodies we used multiple complementary assays, namely ELISA with the SARS-CoV-2 spike protein (specific for IgA and IgG), receptor binding domain (RBD) and nucleocapsid (N) protein for IgG in serum, and bridging ELISA with the SARS-CoV-2 RBD and N protein for specific Ig (IgG, IgM and IgA in human milk and serum). To assess the effect of pasteurization, human milk was exposed to Holder (HoP) and High Pressure Pasteurization (HPP). RESULTS: Human milk contained abundant SARS-CoV-2 antibodies in 83% of the proven cases and in 67% of the suspected cases. Unpasteurized milk with and without these antibodies was found to be capable of neutralizing a pseudovirus of SARS-CoV-2 in (97% and 85% of the samples respectively). After pasteurization, total IgA antibody levels were affected by HoP, while SARS-CoV-2 specific antibody levels were affected by HPP. Pseudovirus neutralizing capacity of the human milk samples was only retained with the HPP approach. No correlation was observed between milk antibody levels and neutralization capacity. CONCLUSIONS: Human milk from recovered COVID-19-infected mothers contains SARS-CoV-2 specific antibodies which maintained neutralization capacity after HPP. All together this may represent a safe and effective immunization strategy after HPP.

Trends and Dynamics in the First Four Years of Operation of the First Human Milk Bank in Vietnam.

BACKGROUND: Since 1979, the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) have recommended the use of pasteurized human milk from a human milk bank (HMB) to feed low birthweight (LBW) and preterm newborns as the 'first alternative' when mothers are unable to provide their own milk. However, they have not issued any guidelines for the safe establishment and operation of an HMB. This gap contributes to the demand for gathering experiences from HMB networks, especially those from lower-middle income countries. To fill this knowledge gap, this study examines the characteristics of donors, donation, pasteurization, and recipients during the first four years of operation in the first HMB in Vietnam. METHODS: Data about the donors, donation, pasteurization, and recipients were extracted from the web-based electronic monitoring system of the HMB from 1 February 2017 to 31 January 2021. RESULTS: In the first four years of operation there were 433 donors who donated 7642 L of milk (66% from the community) with an increased trend in the amount of donated milk, donation duration, and average amount of milk donated by a donor. Approximately 98% of the donated milk was pasteurized, and 82% passed both pre- and post-pasteurization tests. Although the pass rate tended to increase with time, a few dips occurred. Of 16,235 newborns who received pasteurized donor milk, two thirds were in the postnatal wards. The main reason for the prescription of pasteurized donor milk was insufficient mothers' own milk in the first few days after birth. There was a decreased trend in the amount and duration of using pasteurized donor milk in both postnatal wards and the neonatal unit. CONCLUSIONS: The HMB has operated efficiently in the previous four years, even during the COVID-19 pandemic, to serve vulnerable newborns. Ongoing evidence-based adjustments helped to improve the operation to recruit suitable donors, to increase the access to and quality of raw donor milk, to improve the pasteurization process, and to meet the need of more newborns.

Holder pasteurization of donated human milk is effective in inactivating SARS-CoV-2.

BACKGROUND: Provision of pasteurized donor human milk, as a bridge to mother's own milk, is the standard of care for very low-birth-weight infants in hospital. The aim of this research was to confirm that Holder pasteurization (62.5°C for 30 min) would be sufficient to inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in donated human milk samples. METHODS: We spiked frozen milk samples from 10 donors to the Rogers Hixon Ontario Human Milk Bank with SARS-CoV-2 to achieve a final concentration of 1 × 107 TCID50/mL (50% of the tissue culture infectivity dose per mL). We pasteurized samples using the Holder method or held them at room temperature for 30 minutes and plated serial dilutions on Vero E6 cells for 5 days. We included comparative controls in the study using milk samples from the same donors without addition of virus (pasteurized and unpasteurized) as well as replicates of Vero E6 cells directly inoculated with SARS-CoV-2. We reported cytopathic effects as TCID50/mL. RESULTS: We detected no cytopathic activity in any of the SARS-CoV-2-spiked milk samples that had been pasteurized using the Holder method. In the SARS-CoV-2-spiked milk samples that were not pasteurized but were kept at room temperature for 30 minutes, we observed a reduction in infectious viral titre of about 1 log. INTERPRETATION: Pasteurization of human milk by the Holder method (62.5°C for 30 min) inactivates SARS-CoV-2. Thus, in the event that donated human milk contains SARS-CoV-2 by transmission through the mammary gland or by contamination, this method of pasteurization renders milk safe for consumption and handling by care providers.

The impact of thermal pasteurization on viral load and detectable live viruses in human milk and other matrices: a rapid review.

Holder pasteurization (62.5 °C, 30 min) of human milk is thought to reduce the risk of transmitting viruses to an infant. Some viruses may be secreted into milk - others may be contaminants. The effect of thermal pasteurization on viruses in human milk has yet to be rigorously reviewed. The objective of this study is to characterize the effect of common pasteurization techniques on viruses in human milk and non-human milk matrices. Databases (MEDLINE, Embase, Web of Science) were searched from inception to April 20th, 2020, for primary research articles assessing the impact of pasteurization on viral load or detection of live virus. Reviews were excluded, as were studies lacking quantitative measurements or those assessing pasteurization as a component of a larger process. Overall, of 65 131 reports identified, 109 studies were included. Pasteurization of human milk at a minimum temperature of 56-60 °C is effective at reducing detectable live virus. In cell culture media or plasma, coronaviruses (e.g., SARS-CoV, SARS-CoV-2, MERS-CoV) are highly susceptible to heating at ≥56 °C. Although pasteurization parameters and matrices reported vary, all viruses studied, except parvoviruses, were susceptible to thermal killing. Future research important for the study of novel viruses should standardize pasteurization protocols and should test inactivation in human milk. Novelty In all matrices, including human milk, pasteurization at 62.5 °C was generally sufficient to reduce surviving viral load by several logs or to below the limit of detection. Holder pasteurization (62.5 °C, 30 min) of human milk should be sufficient to inactivate nonheat resistant viruses, including coronaviruses, if present.

SARS-CoV-2 in human milk is inactivated by Holder pasteurisation but not cold storage.

AIM: As the COVID-19 pandemic evolves, human milk banks world-wide continue to provide donor human milk to vulnerable infants who lack access to mother's own milk. Under these circumstances, ensuring the safety of donor human milk is paramount, as the risk of vertical transmission of SARS-CoV-2 is not fully understood. Here, we investigate the inactivation of SARS-CoV-2 in human milk by pasteurisation and the stability of SARS-CoV-2 in human milk under cold storage. METHODS: SARS-CoV-2 was experimentally inoculated into human milk samples from healthy donors or into a control medium. Triplicates of each sample were layered onto uninfected cells after Holder pasteurisation (63°C for 30 min), heating to 56°C for 30 min, or after 48 h of storage at 4°C or -30°C. Infectious titres of virus were determined at 72 h post-infection by endpoint titration. RESULTS: Following heating to 63°C or 56°C for 30 min, replication competent (i.e. live) SARS-CoV-2 was undetected in both human milk and the control medium. Cold storage of SARS-CoV-2 in human milk (either at 4°C or -30°C) did not significantly impact infectious viral load over a 48 h period. CONCLUSION: SARS-CoV-2 is effectively inactivated by Holder pasteurisation, suggesting that existing milk bank processes will effectively mitigate the risk of transmission of SARS-COV-2 to vulnerable infants through pasteurised donor human milk. The demonstrated stability of SARS-CoV-2 in refrigerated or frozen human milk may assist in the development of guidelines around safe expressing and storing of milk from COVID-19 infected mothers.

Decontamination of surgical face masks and N95 respirators by dry heat pasteurization for one hour at 70°C.

BACKGROUND: The need for protective masks greatly exceeds their global supply during the current COVID-19 pandemic. METHODS: We optimized the temperature used in the dry heat pasteurization method to destroy pathogens and decontaminate masks while retaining their filtering capacity. RESULTS: The current study showed that dry heat at both 60°C and 70°C for 1 hour could successfully kill 6 species of respiratory bacteria and one fungi species, and inactivate the H1N1 indicator virus. After being heated at 70°C for 1, 2, and 3 hours, the N95 respirators and surgical face masks showed no changes in their shape and components. The filtering efficiency of bacterial aerosol for N95 respirators were 98%, 98%, and 97% after being heated for 1, 2, and 3 hour, respectively, all of which were over the 95% efficiency required and similar to the value before being heated (99%). The filtering efficiency for surgical face masks was 97%, 97%, and 96% for 1, 2, and 3 hours of heating, respectively, all of which were also similar to the value before being heated (97%). CONCLUSIONS: This method can be used at home and can significantly resolve the current shortage of masks.